Lead(II) chromate
 | |
| Names | |
|---|---|
| Other names
see text | |
| Identifiers | |
7758-97-6  | |
| ChEBI | CHEBI:86257  |
| EC Number | 231-846-0 |
| PubChem | 24460 |
| RTECS number | GB2975000 |
| UN number | 3288 |
| Properties | |
| PbCrO4 | |
| Molar mass | 323.2 g/mol |
| Appearance | orange-yellow powder |
| Density | 6.12 g/cm3, solid |
| Melting point | 844 °C (1,551 °F; 1,117 K) |
| negligible | |
| Solubility | soluble in diluted nitric acid insoluble in acetic acid, ammonia |
| Refractive index (nD) |
2.31 |
| Structure | |
| monoclinic | |
| Hazards | |
| Safety data sheet | ICSC 0003 Sigma-Aldrich |
| GHS pictograms |   |
| GHS signal word | Danger |
| H350, H360, H373, H410 | |
| P201, P273, P308+313, P501 | |
| EU classification (DSD) |
Carc. Cat. 2 Repr. Cat. 1/3 Toxic (T) Dangerous for the environment (N) |
| R-phrases | R45, R61, R33, R62, R50/53 |
| S-phrases | S53, S45, S60, S61 |
| NFPA 704 | |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose) |
>12 g/kg (mouse, oral) |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| verify (what is ?) | |
| Infobox references | |
Lead(II) chromate (PbCrO4) is a chemical compound, a chromate of lead. It has a vivid yellow color and is practically insoluble in water, and as a result, is used in paints under the name chrome yellow. It is commonly made in the laboratory by reacting a lead(II) salt (such as lead(II) nitrate) with a chromate or dichromate salt (such as potassium chromate or potassium dichromate) in solution in water, producing a very deep yellow to orange precipitate of lead(II) chromate.
Lead(II) chromate may also be known as chrome yellow, chromic acid lead(II) salt, canary chrome yellow 40-2250, chrome green, chrome green UC61, chrome green UC74, chrome green UC76, chrome lemon, crocoite, dianichi chrome yellow G, lemon yellow, king's yellow, Leipzig yellow, lemon yellow, Paris yellow, pigment green 15, plumbous chromate, pure lemon chrome L3GS, and various other names. The mineral crocoite, occurring as orange-yellow prismatic crystals, is a moderately rare mineral known from the oxidation zones of such Pb ore beds, that were affected by chromate-bearing solutions, coming from the oxidation of primary Cr minerals (chromite) of the nearby (ultra)mafic rocks.
Lead(II) chromate is toxic to humans. It can be attacked by strong reducing agents, combustibles, and organic materials.
Applications
Lead(II) chromate is used in some pyrotechnic compositions, especially delay compositions, as an oxidizer. Up to the late 1800s it was used to impart a bright yellow color to some types of candy.[1] It has also been used in the paint to color school buses.(Chrome Yellow)
Previously, its use was wider. Lead(II) chromate and "white lead", or lead(II) carbonate, were the most common lead-based paint pigments.
Preparation
Lead(II) chromate can be produced by reacting sodium chromate with lead(II) nitrate, or by reacting lead(II) monoxide with a chromic acid solution.
Reactions
Heating in hydroxide solution produces chrome red, a red or orange powder made by PbO and CrO3.
Also, in hydroxide solution lead chromate partially dissolves forming plumbite complex.
- PbCrO4 + 4 OH− → [Pb(OH)4]2− + CrO42−
Safety hazards
Due to containing both lead and hexavalent chromium, lead(II) chromate is profoundly toxic.
Lead(II) chromate is a poison, and can be fatal if swallowed or inhaled.
Lead(II) chromate is a known carcinogen, developmental toxicant, and reproductive toxicant. It is also suspected that lead(II) chromate is a cardivascular or blood toxicant, immunotoxicant, kidney toxicant, neurotoxicant, respiratory toxicant, and a skin toxicant or sense organ toxicant.
If swallowed
If swallowed, lead(II) chromate poisoning can lead to abdominal pain and spasms, nausea, vomiting, and headaches. If the poisoning is not severe, one may experience lead line on the gums, a metallic taste, muscle weakness, and dizziness. The symptoms appear to get worse as the poisoning becomes more severe. Severe poisoning can lead to a coma and even death.
If inhaled
If inhaled, and the poisoning is not severe, one may experience symptoms such as a sore throat, coughing, shortness of breath, and labored breathing. Severe poisoning may lead to pulmonary edema, as well as several symptoms experienced from indigestion.
See also
References
- ↑ Wisconsin. State Board of Health (1887). Progress Report of Public Health in Wisconsin, Volume 10. p. 92. Retrieved 17 July 2013. (Google Books)
| ||||||||||||||